1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Torque vs. weight

  1. Sep 24, 2009 #1
    Hey, I was wondering
    If I have a motor that can supply 6.156 kgf cm of torque operating at 20 rpm, how much weight can that engine move forward given that the radius of the tires will be 5 cm? Please provide equations. Thanks
     
  2. jcsd
  3. Sep 24, 2009 #2
    Hi Cloudswords-
    First, let's convert the motor parameters to power. the torque 6.186 kgf cm is 0.604 Newton-meters, so the power is 0.604 Nm x 20 x 2 pi/60 = 1.26 watts. The power to move the vehicle on a level surface is the velocity times the force to push it, which is 0.01 times the weight W (in Newtons) times the velocity (m/sec), where 0.01 is the expected rolling resistance coefficient of the rubber tires. Using direct drive to the tire, the velocity = [STRIKE]0.104[/STRIKE] 0.658 meters/sec, so the required power is 0.01 W x [STRIKE]0.104[/STRIKE] 0.658 = [STRIKE]0.00104[/STRIKE] 0.00658 W watts.

    So 1.26 watts = [STRIKE]0.00104[/STRIKE] 0.00658 W watts
    So W = [STRIKE]1211[/STRIKE] 191 newtons ([STRIKE]122[/STRIKE] 19.5 Kg)

    [Edit] See table of rolling resistance coefficients in Table near bottom of
    http://en.wikipedia.org/wiki/Rolling_resistance

    Bob S
     
    Last edited: Sep 24, 2009
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Torque vs. weight
  1. Bat Speed vs Bat weight (Replies: 23)

Loading...